Many consumer electronic devices utilize a console that includes various user controls and inputs. In many applications, such as video game consoles, cable television set top boxes and digital video recorders it is desirable to incorporate a microphone into the console. To reduce cost the microphone is typically a conventional omni-directional microphone having no preferred listening direction. Unfortunately, such electronic device consoles also contain noise sources, such as cooling fans, hard-disk drives, CD-ROM drives and digital video disk (DVD) drives. A microphone located on the console would pick up noise from these sources. Since these noise sources are often located quite close to the microphone(s) they can greatly interfere with desired sound inputs, e.g., user voice commands. To address this problem techniques for filtering out noise from these sources have been implemented in these devices.
Most previous techniques have been effective in filtering out broad band distributed noise. For example, fan noise is Gaussian distributed and therefore distributed over a broad band of frequencies. Such noise can be simulated with a Gaussian and cancelled out from the input signal to the microphone on the console. Noise from a disk drive, e.g., a hard disk or DVD drive is characterized by a narrow-band frequency distribution such as a gamma-distribution or a narrow band Laplacian distribution. Unfortunately, deterministic methods that work with Gaussian noise are not suitable for removal of gamma-distributed noise. Thus, there is a need in the art, for a noise reduction technique that overcomes the above disadvantages.